Problem with kit.alias for $types

[teneon]

Describe the bug

When attempting to use kit.alias to set aliases for TypeScript types in the .svelte-kit/types/src/routes directory, TypeScript fails to recognize these aliases unless baseUrl is explicitly set in tsconfig.json. However, setting baseUrl directly conflicts with SvelteKit's built-in behavior of generating tsconfig.json, leading to a warning against such modifications. This creates a challenging scenario where users are unable to utilize custom aliases for auto-generated types, impacting development workflow and code organization.

Reproduction

1. Initialize a standard SvelteKit project with TypeScript enabled.
2. Modify svelte.config.js and add an alias to the kit configuration as follows:

kit: {
  alias: {
    $routes: '.svelte-kit/types/src/routes'
  }
}

3. In my HeaderLeft.svelte component, which is located here: "src/lib/layouts/main/HeaderLeft.svelte"
   By using the added "$routes" alias, the import seems to works properly:
   import type { LayoutData } from '$routes/[[lang=langCode]]/$types';

Without alias i need to import it relative like this and it is cumbersome:
import type { LayoutData } from '../../../routes/[[lang=langCode]]/$types';

4. The issue is that if i add that alias, i also get VSCode error tsconfig.json: Non-relative paths are not allowed when 'baseUrl' is not set. Did you forget a leading './'?

5. If i add baseUrl to the tsconfig.json i get a warning when i do "npm run dev" i get the following message:
   "You have specified a baseUrl and/or paths in your tsconfig.json which interferes with SvelteKit's auto-generated tsconfig.json. Remove it to avoid problems with intellisense. For path aliases, use kit.alias instead: https://kit.svelte.dev/docs/configuration#alias"

So this surely isn't the right way.

6. I have also tried different alias paths to see if it might work, but it didn't work.
   $routes: './svelte-kit/types/src/routes'
   $routes: './.svelte-kit/types/src/routes'
   and so on...
   Either the import via $route didn't resolve anymore or if "." is added in front then i get the other error message: "Non-relative paths are not allowed when 'baseUrl' is not set."

I am not sure if this is a bug / a missing feature or if i don't understand something and i am doing it totally wrong. Please help! Thank you in advance! :)

best regards,
Jim

Logs

npm run dev -- --host

> project@0.0.1 dev
> vite dev --host

You have specified a baseUrl and/or paths in your tsconfig.json which interferes with SvelteKit's auto-generated tsconfig.json. Remove it to avoid problems with intellisense. For path aliases, use `kit.alias` instead: https://kit.svelte.dev/docs/configuration#alias

  VITE v5.2.8  ready in 984 ms

System Info

System:
    OS: Linux 5.15 Ubuntu 22.04.4 LTS 22.04.4 LTS (Jammy Jellyfish)
    CPU: (20) x64 Intel(R) Core(TM) i9-10900K CPU @ 3.70GHz
    Memory: 103.54 GB / 125.69 GB
    Container: Yes
    Shell: 5.1.16 - /bin/bash
  Binaries:
    Node: 20.12.1 - ~/.nvm/versions/node/v20.12.1/bin/node
    npm: 10.5.0 - ~/.nvm/versions/node/v20.12.1/bin/npm
  Browsers:
    Chrome: 123.0.6312.86
  npmPackages:
    @sveltejs/adapter-auto: ^3.2.0 => 3.2.0 
    @sveltejs/kit: ^2.5.5 => 2.5.5 
    svelte: ^4.2.12 => 4.2.12 
    vite: ^5.2.8 => 5.2.8

Severity

annoyance

Additional Information

No response